1. Field of the Invention
The invention herein relates to construction, building and maintenance tools. More particularly it relates to hand-held tools for cutting metal and plastic tubing.
2. Description of the Prior Art
In building and home construction, maintenance, remodeling and the like, cutting of metal or plastic tubing is a common activity. Such tubing is commonly cut for such uses as electrical conduits, water and steam pipes, and air or gas conduits or vents. For large projects where a substantial amount of tubing of a few standardized lengths is needed, tube cutting is usually performed at a tubing mill or other central location using large cutting machines, which are either free standing or are mounted on work benches or similar bases. Such large volume machine cutting is not related to the present invention.
At the other end of the spectrum, for small projects where a modest number of lengths of tubing are to be cut and where the cut lengths typically vary from piece to piece, a worker commonly cuts each piece of tubing with a small hand-manipulated tubing cutter. Such a cutter is operated simply by repeatedly hand-rotating the entire cutter around a longer, uncut length of tubing at the desired cut point, with the cutter blades being hand-moved inwardly in incremental steps after each rotation, so that eventually the blades cut through the tubing. Such hand work, while slow, usually involves few cutting operations which are simple and often performed at widely separated times, so that there is little incentive for the use of more complex cutting tools.
There are many intermediate sized jobs, however, such as construction or remodeling of individual houses, addition of rooms or wings to existing houses, or extension of electrical, water or gas lines into patios, gardens, walkways or other areas immediately surrounding an individual house or building, where a substantial amount of tubing must be cut, often to different lengths and at frequent time intervals. However, such jobs usually do not have the few standard lengths to justify mill cutting or a large enough volume of tubing to justify placement on-site of a cutting machine. In addition, such jobs sites are often at remote or unique locations, so that it is not economic to transport the machine to the job site or to modify the job site to accommodate the machine. In the past, tubing cutting on such intermediate sized jobs has therefore been done by a worker using a conventional hand-manipulated tubing cutter as described above, and making the cuts by the same repeated rotations and blade indexing steps used for the small jobs. For an intermediate sized job, such tasks are tedious, require a significant length of time for each cut of be completed, (particularly for larger diameter or thicker walled tubing) and can cause excessive fatigue of the worker's hands, wrists and arms, and may ultimately results in "repetitive stress" injuries to the worker.